Machines or systems are known for forming flexible sealed pouches or packages containing a consumable product. Such pouches may be made from two continuous films in which a first or base film is vacuum formed to define a pocket to be filled with one or more products or materials and subsequently closed by a second or lid film. Some more recent configurations include multiple compartment pouches and pouches in which more than two films are employed. Particularly suitable applications for flexible packages from water soluble film, such as polyvinyl alcohol (PVA) involve manufacture of individual dosage pouches of laundry detergent and/or dish washing detergent, though other commercial applications are also known.
The nature of the forming process, heating a polymeric film and drawing the film into mold configurations defining cavities or depressions in the film support surface necessarily stretches the film in certain areas to conform with the mold cavity profile. This reduces the original thickness in areas of stretch with a resultant film weakening. It is therefore common practice to design the mold configurations with smooth transition sections having large radii corners between adjoining wall portions to minimize excessive localized stretch and consequent strength reduction.
Moreover, the accepted processing limitation established by film suppliers and followed by pouch manufacturers is that a given film typically should not be stretched to more than twice its pre-forming area. That is, the surface area of unformed film overlying a mold configuration cavity should not be expanded to more than twice this original area.
Heretofore, efforts to provide sharp corner profiles in flexible pouches have been limited to low volume profiles utilizing gradually sloped mold surfaces. This approach has had limited application because it limits the internal volume of the pouch, or increases its overall size, leading to increased cost in film material and processing complexity. Such profiles have heretofore been limited to secondary or ancillary pockets affixed to a main pouch made under traditional forming guidelines. Moreover, these secondary or ancillary pockets require an additional film layer further increasing overall material cost and processing complexity.
Thus, with known systems, it was not possible to produce pouches from two film layers with sharp definition corner profiles and adequate volume capacity in an acceptable pouch size. The present disclosure provides apparatus, mold configurations and methodology to produce pouches with sharp corner definition, which will satisfy the previously unfilled need in the industry. It also provides a simplified approach to forming and filling any shape pouch of polymeric material.